Our objective is to develop a compact device which can generate pure odorant vapor streams at known concentrations ranging from sub-part-per-billion to part-per-million levels in air and to deliver them to test subjects without attenuation or alteration. Such an instrument would allow clinicians to easily measure the olfactory acuity of a person and thereby to test for specific anosmias to one or another of the primary odors. It would also permit the monitoring of any deterioriation of an individual's olfactory sense as a result of being exposed to high concentrations of organic vapors in an industrial environment. These objectives will be achieved by fabricating a gas switching device that will pass binarily incremented air streams through a constant rate odor source and thereafter mixing the odorant stream with the appropriate amount of clean air to dilute the scent to the desired concentrations. This test stream will be delivered to the test subject's nose, unconfounded by spurious odors arising within the instrument or from the external environment, by a suitably heated transfer line leading to a specifically designed nose-piece. The proper functioning to the odorant generator will be monitored by mass spectrometry.
